Important advances have been made in the understanding of the pharmacology of bradykinin receptor. These studies point to a role of the receptor as a powerful hypotensive, proinflammatory mediator. The bradykinin B2 (BKB2) receptor has been identified as an agent in edema, pain and septic shock. At this time little is known of the structural events within the receptor ultimately regulating its functions. Better understanding of the structure/function events could lead to important new therapeutic approaches in dealing with such pathologic states as shock and hypertension. Our results lead us to formulate a working hypothesis stating that receptor uptake and resensitization are linked while receptor desensitization is a separate process. Signal transduction by the receptor is accomplished through a G-protein interaction with motifs within the 2nd, 3rd loops and the C-terminus interacting with the G-protein(s). Phosphorylation within the 2nd IC loop and distal C-terminus initiates receptor uptake. Phosphorylation within the 3rd IC loop initiates desensitization. Resensitization entails dephosphorylation of the receptor. 1. We will investigate receptor function utilizing targeted mutations and chimera exchange. We will continue to test amino acid motif-function relationship. We will explore charge/bulk interactions among distal motifs potentially interactive to produce function and explore the role of phosphorylation of serine/threonine residues in the 2nd and 3rd IC loops and the carboxylic (C) terminus. 2. We will determine regulation of receptor desensitization, resensitization and uptake. We will build on our findings. We will determine if internalization and resensitization are separate or simultaneous events and if uptake is necessary for resensitization. 3. With such procedures as knockout, and G-alpha unit chimera formation, we will determine G-protein/receptor interaction. Because of the evidently predominant BKB2R/Gq interaction we will initially focus on the Gq family with the BKB2 receptor. We will also focus on other subunits such as the G family.